1. Field of the Invention
The present invention relates in general to a reamer, and a method of finishing a hole prepared in a workpiece made of aluminum or other material by using the reamer.
2. Discussion of the Related Art
In the art of finishing a hole prepared in a workpiece made of aluminum or other material with a high degree of roundness of the finished hole and a high degree of smoothness of the inner circumferential surface of the finished hole, a two-blade or a four-blade reamer has been employed. The two-blade reamer has two blades diametrically opposed to each other, and two guide pads each circumferentially spaced apart from the two blades by 90.degree.. The four-blade reamer has four blades which are equiangularly spaced apart from each other by 90.degree. in its circumferential direction. Further, for finishing a hole in a gun barrel or other deep hole, a single-blade reamer (gun reamer) has been conventionally used. However, these conventional reamers are not capable of assuredly satisfying severe reaming requirements, i.e., finishing the hole with a high degree of roundness and a high degree of surface smoothness, for example, a roundness of 7 .mu.m or less and a surface roughness of 6z or less (6 .mu.m or less in ten point height of irregularities (Rz)).